key questions about the early earth
... What was the nature of the pre-biotic terrestrial atmosphere? Noble gas isotopic compositions show that the present-day terrestrial atmosphere is not a direct descendant of whatever atmosphere the Earth may have acquired during planetary accretion. Virtually all of that primordial atmosphere was los ...
... What was the nature of the pre-biotic terrestrial atmosphere? Noble gas isotopic compositions show that the present-day terrestrial atmosphere is not a direct descendant of whatever atmosphere the Earth may have acquired during planetary accretion. Virtually all of that primordial atmosphere was los ...
Structure of the larvikite-lardalite complex, Oslo
... are other contact types which are essentially found along the northern boundary of the complex, west of Tonsberg, but occasionally also in other parts of the region. The discovery of some conspicious textures along an internal boundary between two lardalite variants led the present author to regard ...
... are other contact types which are essentially found along the northern boundary of the complex, west of Tonsberg, but occasionally also in other parts of the region. The discovery of some conspicious textures along an internal boundary between two lardalite variants led the present author to regard ...
Anorthosite and the lower crust
... Experimental data on the basaltic systems in dry conditions have considerably modified the consensus view on the nature and source of the parent magma ponding in the deep-seated magma chamber (Longhi et al., 1999). The data show that the parent magma composition of anorthosite massifs (high-alumina ...
... Experimental data on the basaltic systems in dry conditions have considerably modified the consensus view on the nature and source of the parent magma ponding in the deep-seated magma chamber (Longhi et al., 1999). The data show that the parent magma composition of anorthosite massifs (high-alumina ...
Sulfur in weathering and sedimentary processes
... Sulfur in weathering and sedimentary processes The global sulfur cycle is a complex network of processes that transfer sulfur between four main reservoirs: the ocean, the ocean floor basalts, evaporite deposits and reduced marine sediments (the latter are the largest reservoir of sulfur). By compar ...
... Sulfur in weathering and sedimentary processes The global sulfur cycle is a complex network of processes that transfer sulfur between four main reservoirs: the ocean, the ocean floor basalts, evaporite deposits and reduced marine sediments (the latter are the largest reservoir of sulfur). By compar ...
(43.5-46°S): Implications for Magma Genesis
... differences further elaborated on by Naranjo and Stern (1998, 2004) and Watt et al. (2012). These studies have demonstrated that both Hudson and Melimoyu volcanoes are HA types, Yanteles, Maca and Cay are LA type, and Huequi and Mentolat are VLA type centers (Figs 1 and 2). However, a number of fir ...
... differences further elaborated on by Naranjo and Stern (1998, 2004) and Watt et al. (2012). These studies have demonstrated that both Hudson and Melimoyu volcanoes are HA types, Yanteles, Maca and Cay are LA type, and Huequi and Mentolat are VLA type centers (Figs 1 and 2). However, a number of fir ...
The Laramide Orogeny: What Were the Driving Forces?
... regardless of which plate was subducting beneath it, it seems unlikely that slab age or convergence rate were the principal driving force of orogenesis. It is possible that a ~100 km eastward migration of arc magmatic belts in western Canada and Mexico during Laramide time (e.g., van der Heyden, 199 ...
... regardless of which plate was subducting beneath it, it seems unlikely that slab age or convergence rate were the principal driving force of orogenesis. It is possible that a ~100 km eastward migration of arc magmatic belts in western Canada and Mexico during Laramide time (e.g., van der Heyden, 199 ...
as a PDF
... The modern Japanese Islands geographically comprise five island arcs: the Kurile, Northeast Japan, Izu-Bonin, Southwest Japan, and Ryukyu arcs, showing complex patterns common in the western Pacific. Four of these form segments of active island arcs between the Eurasian continent and the Pacific Oce ...
... The modern Japanese Islands geographically comprise five island arcs: the Kurile, Northeast Japan, Izu-Bonin, Southwest Japan, and Ryukyu arcs, showing complex patterns common in the western Pacific. Four of these form segments of active island arcs between the Eurasian continent and the Pacific Oce ...
The Laramide Orogeny - University of Nevada, Reno
... regardless of which plate was subducting beneath it, it seems unlikely that slab age or convergence rate were the principal driving force of orogenesis. It is possible that a ~100 km eastward migration of arc magmatic belts in western Canada and Mexico during Laramide time (e.g., van der Heyden, 199 ...
... regardless of which plate was subducting beneath it, it seems unlikely that slab age or convergence rate were the principal driving force of orogenesis. It is possible that a ~100 km eastward migration of arc magmatic belts in western Canada and Mexico during Laramide time (e.g., van der Heyden, 199 ...
McLelland, JM, Selleck, BW, and Bickford, ME, 2010
... advances in understanding of the Precambrian tectonic evolution of the Grenville Province, including its Adirondack outlier, and the Mesoproterozoic inliers of the Appalachians. Based upon this information, we review the geochronology and tectonic evolution of these regions and significant similarit ...
... advances in understanding of the Precambrian tectonic evolution of the Grenville Province, including its Adirondack outlier, and the Mesoproterozoic inliers of the Appalachians. Based upon this information, we review the geochronology and tectonic evolution of these regions and significant similarit ...
Indonesia The geology and tectonic evolution of the Bacan region
... arc-related Sibela ophiolite, probably derived from the Philippine Sea plate. Isotopic dating yielded a Cretaceous age with an Oligocene-Miocene overprint. In north Bacan, the oldest formation is the Upper Eocene Bacan Formation which comprises interbedded arc volcanic and turbiditic volcaniclastic ...
... arc-related Sibela ophiolite, probably derived from the Philippine Sea plate. Isotopic dating yielded a Cretaceous age with an Oligocene-Miocene overprint. In north Bacan, the oldest formation is the Upper Eocene Bacan Formation which comprises interbedded arc volcanic and turbiditic volcaniclastic ...
Answer Key
... metamorphism that occurs near igneous intrusions, where magma comes into direct contact with surrounding rock. Regional metamorphism is a type of metamorphism that occurs when large pieces of Earth’s crust collide, causing rock to become deformed and chemically changed over large areas. 4. Because i ...
... metamorphism that occurs near igneous intrusions, where magma comes into direct contact with surrounding rock. Regional metamorphism is a type of metamorphism that occurs when large pieces of Earth’s crust collide, causing rock to become deformed and chemically changed over large areas. 4. Because i ...
Minerals - TeacherWeb
... Some minerals have more than one element. These minerals are made of compounds of elements. (think compound ...
... Some minerals have more than one element. These minerals are made of compounds of elements. (think compound ...
Serpentinites - Elements Magazine
... occur near the base of the mantle wedge at depths greater than 10 km. In some forearc environments, buoyant serpentinites have been exhumed to the seafloor along normal faults and through tectonic processes, such as subduction erosion and the return flow of subducted material in a subduction channel ...
... occur near the base of the mantle wedge at depths greater than 10 km. In some forearc environments, buoyant serpentinites have been exhumed to the seafloor along normal faults and through tectonic processes, such as subduction erosion and the return flow of subducted material in a subduction channel ...
geology and chromite deposits of the camaguey district camaguey
... a substantial part of the refractory-grade chromite used in this country during the war. The ore occurs in a complex that consists mainly of serpentinized peridotite and dunite with minor amounts of gabbro, troctolite, and anorthosite. The complex was intruded into metamorphic rocks, and is unconfor ...
... a substantial part of the refractory-grade chromite used in this country during the war. The ore occurs in a complex that consists mainly of serpentinized peridotite and dunite with minor amounts of gabbro, troctolite, and anorthosite. The complex was intruded into metamorphic rocks, and is unconfor ...
Template Abstract Soultz Conference - Hal-BRGM
... geothermal energy exploitation especially in continental rifting as the Upper Rhine Graben. This unconformity presents lot of natural fractures which constitute a large permeable fracture network driving brine movement. That constitutes a reservoir of hot water, which is exploited by several geother ...
... geothermal energy exploitation especially in continental rifting as the Upper Rhine Graben. This unconformity presents lot of natural fractures which constitute a large permeable fracture network driving brine movement. That constitutes a reservoir of hot water, which is exploited by several geother ...
Tapoban Geothermal Field, Alaknanda Valley, Chamoli, Uttarakhand
... shallow depth has been reported followed by a high resistive zone. At Badrinath lower order resistivity is in the range of 60 to 250 Ohm-m with thickness ranging from 20 to 250 m. At Tapoban a shallow conductive layer of the order 90 Ohm m at the depth 20 to 100m has been envisaged. The low conducti ...
... shallow depth has been reported followed by a high resistive zone. At Badrinath lower order resistivity is in the range of 60 to 250 Ohm-m with thickness ranging from 20 to 250 m. At Tapoban a shallow conductive layer of the order 90 Ohm m at the depth 20 to 100m has been envisaged. The low conducti ...
LODE-GOLD DEPOSITS
... inch to at least green to grey, and frequently reddish, fragments, which range from 2 feet in diameter. The larger fragments are set in a finer-grained ground-mass of similar colour. Bedding is seldom seen in the coarser fragmental types. Tuffs, representing the finer-grained equivalents of the brec ...
... inch to at least green to grey, and frequently reddish, fragments, which range from 2 feet in diameter. The larger fragments are set in a finer-grained ground-mass of similar colour. Bedding is seldom seen in the coarser fragmental types. Tuffs, representing the finer-grained equivalents of the brec ...
ORGANIC GEOCHEMISTRY OF CRUDE OILS FROM
... Geologic age of the source rocks of the Zrenjanin oils was evaluated using the age-specific biomarker ratios: oleanane index (OI; Moldowan et al., 1994) and nordiacholestane ratio (NDR; Holba et al., 1998). These results indicated Tertiary age for the studied oils. However, the mean values of OI for ...
... Geologic age of the source rocks of the Zrenjanin oils was evaluated using the age-specific biomarker ratios: oleanane index (OI; Moldowan et al., 1994) and nordiacholestane ratio (NDR; Holba et al., 1998). These results indicated Tertiary age for the studied oils. However, the mean values of OI for ...
ch 4
... Challis Arc igneous rocks range from about 55 to 40 million years in age, with most falling between 50 and 45 million years ago. Most (but not all) of these plutons appear to have intruded along fault zones, shear zones or other tectonic features. They characteristically rose to shallow depths, and ...
... Challis Arc igneous rocks range from about 55 to 40 million years in age, with most falling between 50 and 45 million years ago. Most (but not all) of these plutons appear to have intruded along fault zones, shear zones or other tectonic features. They characteristically rose to shallow depths, and ...
Basin development and deposition of the Bongaya Formation in the
... The sedimentological and structural features of the Bongaya sediments suggest that the deposition of these sediments was closely controlled by earlier major structures. Based on earlier studies (Tongkul, 1989), the underlying sediments were found to have been folded and thrust-faulted with their fol ...
... The sedimentological and structural features of the Bongaya sediments suggest that the deposition of these sediments was closely controlled by earlier major structures. Based on earlier studies (Tongkul, 1989), the underlying sediments were found to have been folded and thrust-faulted with their fol ...
Fluid evolution within Eastern Rhodopian sedimentary rock
... barren, but are variably altered to sericite, chlorite, clay minerals, and pyrite-hematite assemblages in a ductile-brittle transition zone, below the detachment. However, at one of the prospects, i.e. Surnak, this transition zone is displaced to deeper crustal levels, within the metamorphic basemen ...
... barren, but are variably altered to sericite, chlorite, clay minerals, and pyrite-hematite assemblages in a ductile-brittle transition zone, below the detachment. However, at one of the prospects, i.e. Surnak, this transition zone is displaced to deeper crustal levels, within the metamorphic basemen ...
petrology and isotope systematics of magma mushes
... REGIONAL SETTING These bodies are emplaced into the Borborema tectonic province, a complex structural mosaic of linear metasedimentary fold belts separated by massifs of much older, previously deformed gneissic basement (Almeida et aI. 1981). The final major orogeny in this area was the Brasiliano C ...
... REGIONAL SETTING These bodies are emplaced into the Borborema tectonic province, a complex structural mosaic of linear metasedimentary fold belts separated by massifs of much older, previously deformed gneissic basement (Almeida et aI. 1981). The final major orogeny in this area was the Brasiliano C ...
Geology and Geotectonic Setting of the Basement Complex
... quartz and the biotite flakes form thin foliation bands which are closely packed around garnet crystals. In some of the cores examined recovery failures are recorded indicating fracturing as described above. This biotite granite gneiss contains deformation fabrics which may be regarded as D2 and pro ...
... quartz and the biotite flakes form thin foliation bands which are closely packed around garnet crystals. In some of the cores examined recovery failures are recorded indicating fracturing as described above. This biotite granite gneiss contains deformation fabrics which may be regarded as D2 and pro ...
A petrologic case for Eocene slab break
... and/or several kilometers of Miocene exhumation due to extensional faulting. Sparse Oligocene to Eocene ages are often assigned to a tectonically unspecified event. An alternative slab-breakoff model (subduction of Greater Himalayan rocks to ;100 km depth in the Eocene followed by buoyant extrusion ...
... and/or several kilometers of Miocene exhumation due to extensional faulting. Sparse Oligocene to Eocene ages are often assigned to a tectonically unspecified event. An alternative slab-breakoff model (subduction of Greater Himalayan rocks to ;100 km depth in the Eocene followed by buoyant extrusion ...
Algoman orogeny
The Algoman orogeny, known as the Kenoran orogeny in Canada, was an episode of mountain-building (orogeny) during the Late Archean Eon that involved repeated episodes of continental collisions, compressions and subductions. The Superior province and the Minnesota River Valley terrane collided about 2,700 to 2,500 million years ago. The collision folded the Earth's crust and produced enough heat and pressure to metamorphose the rock. Blocks were added to the Superior province along a 1,200 km (750 mi) boundary that stretches from present-day eastern South Dakota into the Lake Huron area. The Algoman orogeny brought the Archaen Eon to a close, about 2,500 million years ago; it lasted less than 100 million years and marks a major change in the development of the earth’s crust.The Canadian shield contains belts of metavolcanic and metasedimentary rocks formed by the action of metamorphism on volcanic and sedimentary rock. The areas between individual belts consist of granites or granitic gneisses that form fault zones. These two types of belts can be seen in the Wabigoon, Quetico and Wawa subprovinces; the Wabigoon and Wawa are of volcanic origin and the Quetico is of sedimentary origin. These three subprovinces lie linearly in southwestern- to northeastern-oriented belts about 140 km (90 mi) wide on the southern portion of the Superior Province.The Slave province and portions of the Nain province were also affected. Between about 2,000 and 1,700 million years ago these combined with the Sask and Wyoming cratons to form the first supercontinent, the Kenorland supercontinent.